Cardiac surgery with cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response, increase in oxidative stress, and upregulation of inflammatory mediators including C-reactive protein (CRP), interleukin 6 (IL-6), and B-type natriuretic peptide (BNP). Increased systemic inflammation is a risk factor for worse post-operative (postop) outcomes including the development of acute kidney injury (AKI) and atrial fibrillation (AF). It has been shown that inflammation induced oxidative stress leads to reduced nitric oxide (NO) bioavailability and concentration in tissues. See Cai, et al. (2002) Circulation 106:2854-2858 (NO measured in left atrial and aortic samples in a porcine model of AF). Unfortunately, measuring NO in tissues require invasive tissue biopsies, which may increase the risk of postop complications, or may only be performed post-mortem.
Thus, a need exists for methods for screening and monitoring postop complications such as systemic inflammation, and development of postop AF and AKI, which are particularly prevalent in surgical patients having high morbidity and/or high mortality, in subjects without further increasing their risk of postop complications.